My overall career goal is to establish an independent program of research focusing on identifying novel interventions to decrease the morbidity and mortality associated with nocturnal hypertension (HTN), defined as having elevated blood pressure (BP) during sleep on 24-hour ambulatory BP monitoring (ABPM). Training plan: In the K23 Career Development Award application, I will obtain training in four areas in order to build an independent program of research with an expertise in HTN and sleep: Module 1: Research Methodology in HTN including Clinical Trials, Module 2: Clinical and Research Training in Sleep including Clinical Trials, Module 3: Quantitative Methodologies and Advanced Statistics in HTN, and Module 4: Research Dissemination and Transition to Independence. I have assembled a multidisciplinary team of senior investigators with expertise in HTN (Drs. Daichi Shimbo, Joseph Schwartz, and Paul Muntner), sleep research (Drs. Ari Shechter and Martica Hall), biostatistics (Dr. Schwartz), and randomized controlled trials (RCTs) (Drs. Schwartz and Shechter) who will meet regularly with me to ensure that I am progressing towards my research and training goals, and overall career development. Research plan: Individuals with higher sleep BP levels are at an increased risk of target organ damage and cardiovascular disease (CVD) events. Short sleep duration (SSD) defined as sleeping less than 7 hours per night, occurs in over 30% of adults, and is associated with an increased risk for CVD. Cross-sectional studies have shown that SSD is associated with elevated sleep BP levels which may be due to increased sympathetic activity and reduced parasympathetic activity. I will conduct a RCT to determine the effect of an 8-week sleep extension intervention on sleep BP as assessed on 24-hour ABPM among 66 individuals with SSD. Participants will be randomized to sleep extension (a validated sleep hygiene education intervention), aiming to increase sleep duration by up to 1 hour over 8 weeks as assessed by wrist actigraphy (n=33) vs. a control condition (education on sleep physiology; n=33). Participants will have 24-hour ABPM and standardized assessment of sympathetic and parasympathetic activity during 24- hour ABPM at baseline and 8 weeks later. I will determine whether sleep extension is associated with a reduction in mean sleep systolic BP, and secondarily, mean sleep diastolic BP (Primary Aim). I will examine whether sleep extension is associated with a reduction in sympathetic activity and an increase in parasympathetic activity from baseline to 8 weeks (Secondary Aim 1). The degree to which a reduction in mean sleep systolic BP with the sleep extension intervention is explained by a reduction in sympathetic and parasympathetic activity will also be examined (Secondary Aim 2). The analyses for the Primary Aim will also be stratified by nocturnal HTN and poor sleep quality status at baseline (Exploratory Aim). This study will provide a strong foundation for my planned career in HTN and sleep, and a future R01 proposal examining whether sleep extension reduces the increased CVD risk associated with higher sleep BP levels.